| Abstract |
Our principal theory of spacetime, general relativity, is in foundational conflict with quantum mechanics. A century since their advent, the theories together explain all known physical phenomena, but no data exists at their intersection. The quantum structure of spacetime was long thought to manifest only at the Planck scale, 10^-35 m or 10^-44 s. The holographic principle provides a promising path to experimentation: The universe may have 2-dimensional upper bounds on quantum information, like the 2-dimensional causal horizons of black holes, the densest objects possible. This bandwidth limit may cause a precise ruler or clock to see "pixelation," an irreducible indeterminacy of empty spacetime itself, at the scale of measuring the solar system size to 1/100 of an atom- a scale within reach of state-of-the-art laser interferometry developed for LIGO. A table-top experiment to search for such experimental signatures of quantized space-time is under construction at Cardiff University, supported by UKRI's Quantum Technologies for Fundamental Physics program, the Leverhulme Trust, the Wolfson Foundation, and STFC equipment grants. In the proposed exchange visit, we will investigate the possibility of isolating a few signal-carrying photons from a beam of 10^25 others for readout by superconducting single photon detectors. This would be a completely new readout scheme for high-power laser interferometers, applicable to fundamental physics research and possibly beyond. |
